I'm a bit embarrassed to admit this, but at times, I have written just "thank you" to people (it wasn't me Tea; I've never commented on a blog there)....it's because I didn't know what else to write.
But sometimes I'll write more than that, and then think, "wow, this sounds patronizing", or like I'm trying to "one-up" the person's experience, and so I erase it and just leave the "thank you".
I actually do that here - I'll erase most of a post, or delete it altogether.
Edit to add:
So, if I ever write just "thank you", here's my translation: "I really related to that; and I appreciate that you've shared it."
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Aspie score: 161 of 200
Neurotypical (non-autistic) score: 38 of 200
Autistic/BAP -123 aloof, 124 rigid and 108 pragmatic
Autism Spectrum quotient: 41, Empathy Quotient: 19